1. Field of the Invention
The present invention relates to a composite building material manufactured by combining, for instance, a foamed synthetic resin material with a concrete material or with a reinforcing material and also to a method for manufacturing the composite building material, the composite building material ensuring that floor materials, framework walls and the like in, for instance, various buildings, e.g., general houses and residences, can be formed firmly in a simple and speedy manner.
2. Description of the Related Art
In customary production of this type of composite building material, for instance, when a cement mortar material is bonded with, for example, a flat plate-like foamed polystyrene board which is a heat-insulating material made of a foamed synthetic resin material, both materials are bonded with each other either by the adhesion of the cement mortar material itself or by using an adhesive thereby integrating the foamed polystyrene board with the cement mortar material. The adhesive include resin-soluble types and resin-insoluble types in which a synthetic rubber powder is compounded.
However, in the prior art, when the foamed synthetic resin plate layer is bonded with the cement mortar material only by the adhesion of the cement mortar material itself, both materials are easily separated from each other to produce cracks on account of very week adhesion, bringing about defects in strength for building materials. On the other hand, when the adhesive is used, the adhesive durability is reduced due to the deterioration of the adhesive itself caused by, for instance, a variation in the elastic modulus with time and denaturing of the composition and hence there is a possibility of exfoliations. Also, when the aforementioned resin-soluble adhesive is used, it solves part of the foamed synthetic resin plate layer, whereby clearances are produced between the foamed synthetic resin plate layer and the cement mortar layer and nonuniformity in the thickness of the foamed synthetic resin plate layer is caused. This is the cause of cracks and exfoliations. The aforementioned resin-insoluble adhesive formulated with a synthetic rubber powder is very expensive and hence the use of the resin for composite building materials is not very practical. Moreover, because the conventional composite building material using a foamed synthetic resin material is not provided with any reinforcing treatment for preventing buckling against bending stress, it has inferior strength particularly when it is used as a floor material and is not used very widely as framework wall materials for composite building materials.